The use of brominated and/or chlorinated compounds by themselves or in combination with other materials such as organic phosphates, boron compounds, etc., as flame retardants for resin compositions is well known in the art. For example, U.S. Pat. No. 3,775,165 of Young et al. describes halogenated aromatic dicarboxylic acid diesters useful for improving the flame retarding and dyeing properties of polyester fibers and polypropylene polymers and fibers.
Further, tetrahalophthalate esters have been used as flame-proofing materials. For example, U.S. Pat. No. 4,098,704 of Sandler describes the use of these materials as textile finishing agents. U.S. Pat. Nos. 4,298,517 and 4,397,977 of Sandler disclose these compounds as flame retardants for halogenated resins. U.S. Pat. No. 4,762,861 of Bohen et al. discloses tetrahalophthalate esters as flame retardant processing aids for polystyrene resins.
Polyhalophenyl esters have been used as flame-proofing materials either as additives to plastics or incorporated as part of the polymer backbone. Examples of the latter are polyhalophenyl esters of polymerizable acids such as 2,4,6-tribromophenyl methacrylate, pentabromophenyl methacrylate, 2,4,6-tribromophenyl acrylate, pentachlorophenyl methacrylate, pentabromophenyl acrylate, trichlorophenyl acrylate, tetrabromoxylylene di(methacrylate), etc., which are exemplified by U.S. Pat. Nos. 3,207,731; 3,210,326; 3,845,102; 3,932,321; 4,032,509; 4,048,263; 4,105,628; 4,108,943; 4,110,296; 4,205,153; and 4,415,704, the disclosures of which are incorporated herein by reference.